In social systems, understanding the dynamics of microbial sharing remains critical for infectious disease control. In nonhuman primates, heterogeneity in social networks is being increasingly modeled to assess such sharing. Here we use phylogenetics and social networks to assess commensal bacterial (Escherichia coli) sharing among three captively-housed rhesus macaque (Macaca mulatta) groups. Behavioral data on grooming, huddling and aggression were used to reconstruct weighted, undirected, contact-networks using a clustering method – Data Cloud Geometry. Bacterial similarity was inferred by calculating phylogenetic distances between DNA fingerprint profiles generated by processing macaque fecal samples using Pulsed Field Gel Electrophoresis. GLMMs showed that in two macaque groups, pairwise similarity in E. coli was higher among young-young (B=4.83, df=3073, p<0.01) and male-male dyads (B=3.83, df=3073, p<0.01), but unrelated to social contact frequencies. At the community level, E. coli similarity was significantly greater among macaques within the same compared to different behavioral communities for all three groups (e.g. Group III grooming: D=0.81, p<0.01). Our findings suggest that in spatially constrained, frequently interacting monkeys, microbial sharing may be discernible across clusters of connected community members, rather than between dyads. Future work will aim to link E. coli sharing to macaques' shared space-use, and assess microbial transmission by constructing directed networks.